S-98164A517 1/4"-20 x 5/16" ASME B18.3, ASTM F879 Stainless Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 stainless steel construction and passivated finish, ideal for harsh chemical and marine environments
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B55 hardness for heavy-duty applications
• Precise thread engagement with Class 3A UNC coarse threads ensuring reliable fastening in demanding conditions
• Easy installation and removal with 5/32" hex drive design providing secure tool engagement and reduced slippage
• Optimized load distribution through rounded button head design that minimizes surface stress concentrations
• Full thread coverage along the 5/16" length for maximum grip strength and vibration resistance
• Regulatory compliance assurance meeting ASME B18.3 standards and environmental regulations including RoHS 3 and REACH

Professional Applications & Engineering Value

These 316 stainless steel rounded head screws deliver exceptional performance in corrosive environments where standard fasteners fail. The combination of Class 3A UNC coarse threading and passivated finish provides superior resistance to chemical attack, making them ideal for chemical processing equipment, marine hardware, and food processing machinery. The hex drive configuration ensures positive torque transmission during installation, while the rounded button head design offers a clean aesthetic finish with reduced protrusion. Engineered to withstand extreme conditions, these screws maintain their 70,000 psi tensile strength in high-stress applications, providing reliable fastening solutions for industrial assemblies requiring both durability and corrosion resistance.

Specification Summary & Compliance

This 1/4"-20 UNC screw features Class 3A thread fit precision with coarse thread spacing for optimal engagement. Manufactured to ASME B18.3 specifications (ASTM F879) with full compliance to RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards. The 5/16" length provides complete threading coverage, while the Rockwell B55 hardness rating ensures dimensional stability under load. The passivated surface treatment enhances the natural corrosion resistance of 316 stainless steel, making these screws suitable for regulated industries requiring documented material compliance.